旅行者号2号（Voyager 2）航天器于49年前的今天发射

旅行者号2号实现了对带外行星进行大巡游的构想。它是唯一一艘造访过全部4颗带外行星的航天器。

Voyager 2 realized the vision of what was originally called a Grand Tour of the outer solar system. It is the only craft that has visited all 4 outer planets. The post Voyager 2 spacecraft launched 49 years ago today first appeared on EarthSky .